The present invention relates to a playback control apparatus used together with a playback device such as digital video disk (DVD), video compact disk (VCD), video cassette recorder (VCR), or the like. The present invention also relates to a television receiver (TV) when the TV is used as a replacement for the above playback control apparatus. The present invention further relates to a technique applicable to a device such as a television monitor or a TV, both having the ability to view played back material.
When a playback control apparatus is used with a conventional playback device such as DVD, VCD, VCR or the like as a system, a control device which controls those apparatus is occasionally designed to switch an output signal of the playback apparatus to/from a television receiving signal, and also control the playback apparatus at the same time.
For example, Japanese Patent Application Publication H07-240882 discloses a control device of a TV which has a playback apparatus: when a user displays a television broadcasting program on a TV screen while the user operates the playback apparatus, this control device first stops the operation of the playback apparatus, then selects a television signal with a switch. If the stop will last for a specified period, a power supply for the playback apparatus is then turned off. As explained above, one action of the user ignites the control device to work relevant control operations sequentially, i.e. switching the two signal sources with ease.
A playback apparatus attached to a TV through which the playback apparatus can be controlled is disclosed in Japanese Utility Model Publication S60-47373: this TV includes a terminal tapping off of a remote control signal, and thereby controlling the outside apparatus with the remote control signal; however, a control function of the television monitor used together with those conventional playback apparatus, or that of the TV having the built-in playback apparatus, is limited only to hold the operation of the playback apparatus, to switch an input signal to another input signal, and to turn off the power of the playback apparatus after the specified period. In other words, the controllable functions of this control device only covers related operations between those apparatus, and neither covers the operation of the playback apparatus, nor optimizes a display responding to the condition of the playback apparatus.
As a result, when a cathode ray tube (CRT) is used as a display device of the monitor or the TV, the control device cannot control the display device. Thus, for example, a playback signal which has been paused may burn out a spot of the CRT screen, or lower phosphor characteristics. Further, when switching to a playback mode, an unnecessary circuit may remain active, and the control device may not deactivate unnecessary circuits at all, thereby loosing an opportunity to save energy.
These problems are also applicable to other display devices including a liquid crystal display (LCD) and a plasma display. When a CRT projector is used as a display device, the lens coating may be deteriorated due to excessive heating.
A playback control apparatus according to the present invention comprises:
a playback unit for reproducing a video signal and/or an audio signal, (2) a display device for displaying the reproduced video signal and/or audio signal, (3) a playback and/or display control device for controlling the display responding to a playback status. A control device deactivates unnecessary circuits in order to save energy of the system.